U.S. patent application number 12/808079 was filed with the patent office on 2010-12-23 for antenna array for a radar transceiver and circuit configuration for supplying an antenna array of such a radar transceiver.
Invention is credited to Juergen Hasch, Ewald Schmidt.
Application Number | 20100321268 12/808079 |
Document ID | / |
Family ID | 40336453 |
Filed Date | 2010-12-23 |
United States Patent
Application |
20100321268 |
Kind Code |
A1 |
Hasch; Juergen ; et
al. |
December 23, 2010 |
Antenna array for a radar transceiver and circuit configuration for
supplying an antenna array of such a radar transceiver
Abstract
An antenna array for radar transceivers, in particular for
ascertaining distance and/or speed in the surroundings of vehicles,
a first antenna part being situated on a carrier and a second
antenna part being situated on another carrier situated at a
distance from the first. The first antenna part has two generally
rectangular primary exciter patches which adjoin each other on one
edge, where they are short-circuited toward ground, two primary
exciter patches have two separate supply lines, and the second
antenna part comprises two mutually separated rectangular secondary
exciter patches, which partially cover the primary exciter patches
and which have, in the region of the ground short-circuit of the
primary exciter patches, in the beam direction, a distance from
each other that at least exposes the ground short-circuit.
Inventors: |
Hasch; Juergen; (Stuttgart,
DE) ; Schmidt; Ewald; (Ludwigsburg, DE) |
Correspondence
Address: |
KENYON & KENYON LLP
ONE BROADWAY
NEW YORK
NY
10004
US
|
Family ID: |
40336453 |
Appl. No.: |
12/808079 |
Filed: |
October 21, 2008 |
PCT Filed: |
October 21, 2008 |
PCT NO: |
PCT/EP08/64165 |
371 Date: |
September 10, 2010 |
Current U.S.
Class: |
343/818 |
Current CPC
Class: |
H01Q 9/0414 20130101;
H01Q 25/02 20130101; H01Q 1/3233 20130101; H01Q 3/30 20130101; H01Q
9/0421 20130101; H01Q 19/062 20130101 |
Class at
Publication: |
343/818 |
International
Class: |
H01Q 19/00 20060101
H01Q019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 17, 2007 |
DE |
10 2007 060 770.0 |
Claims
1-9. (canceled)
10. An antenna array for a radar transceiver for ascertaining at
least one of distance and speed in surroundings of a vehicle,
comprising: a first antenna part situated on a first carrier, the
first antenna part including two generally rectangular primary
exciter patches which adjoin each other on one edge where they are
short-circuited to ground, each of the two primary exciter patches
having a separate supply line; and a second antenna part situated
on a second carrier, at a distance from the first carrier, the
second antenna part including two mutually separated rectangular
secondary exciter patches which partially cover the primary exciter
patches and which have in a region of the ground short-circuit of
the primary exciter patches in the beam direction a distance from
each other that at least exposes the ground short-circuit.
11. The antenna array as recited in claim 10, wherein the carrier
carrying the primary exciter patches is one of a chip, a circuit
board, a soft board substrate or a circuit film.
12. The antenna array as recited in claim 10, wherein the carrier
carrying the secondary exciter patches is one of a circuit board, a
soft board substrate or a circuit film.
13. The antenna array as recited in claim 10, wherein the first and
second carriers are fastened to each other and mutually contacted
by flip-chip connections.
14. The antenna array as recited in claim 10, wherein both
secondary exciter patches are situated at least one of on a top
side and on a bottom side of the second carrier.
15. The antenna array as recited in claim 10, wherein the supply
lines of the primary exciter patches are connected on longitudinal
edges of the primary exciter patches, a terminal position of the
supply lines being selectable depending on a desired, specifiable
impedance of the antenna array.
16. The antenna array as recited in claim 10, wherein a space
between the first and second carriers is filled by an encapsulating
material embedding the primary exciter patches and the secondary
exciter patches, the encapsulating material being one of a silicone
gel or an underfiller on epoxide resin.
17. A circuit device for supplying primary exciter patches of an
antenna array, the antenna array including a first antenna part
situated on a first carrier, the first antenna part including two
generally rectangular primary exciter patches which adjoin each
other on one edge where they are short-circuited to ground, each of
the two primary exciter patches having a separate supply line, and
a second antenna part situated on a second carrier, at a distance
from the first carrier, the second antenna part including two
mutually separated rectangular secondary exciter patches which
partially cover the primary exciter patches and which have in a
region of the ground short-circuit of the primary exciter patches
in the beam direction a distance from each other that at least
exposes the ground short-circuit, the circuit device comprising: a
switching device in which in one switch position a high-frequency
signal is applicable to the supply terminal of the first exciter
patch and a high-frequency signal having a phase shift of
180.degree. is applicable to the supply terminal of the second
primary exciter patch, and in the second switch position of which
respectively an in-phase high-frequency signal is applicable on the
first supply line of the first primary exciter patch and on the
second supply line of the second primary exciter patch.
18. The circuit device as recited in claim 17, wherein an amplitude
of the high-frequency signal applied on at least one supply
terminal in the first switch position of the switching device is
adjustable for swiveling a beam cone.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an antenna array for a
radar transceiver, in particular for ascertaining distance and/or
speed in the surroundings of vehicles, and a circuit configuration
for supplying the primary exciter patches of such an antenna
array.
BACKGROUND INFORMATION
[0002] Radar transceivers, i.e. transmitting/receiving modules, are
used in the microwave and millimeter wave range for locating
objects in space or for determining the speed, for example of
vehicles. Radar transceivers are also used for example for driver
assistance systems, which are used, e.g., for determining the
distance of another vehicle traveling ahead of a host vehicle as
well as for adaptive cruise control. For the purpose of locating
objects in space and for determining the speed, such a radar
transceiver emits signals at the highest frequency in the form of
electromagnetic waves, which are reflected by the target object and
are received again by the radar transceiver and processed. In many
cases, several of these radar transceivers are wired up to form an
overall module.
[0003] A radar sensor is described in German Patent Application No.
DE 10 2005 056 756 A1, in which a part of the antenna is situated
directly on a semiconductor circuit, while a second part is
situated on a carrier that is positioned at a distance above the
first part. Such a radar sensor generally has an antenna
characteristic, i.e., a beam characteristic, that is predetermined
by the type of construction.
SUMMARY
[0004] An object of the present invention is to develop an antenna
array in such a way that it is usable for different beam
characteristics. In particular, it is to be used as a monopulse
antenna. Monopulse antennas are antenna groups, the individual
antennas of which are not merely interconnected to form a sum, but
in which other circuit options may be implemented as well. In
particular, various differences may be formed for different
purposes. By comparing the amplitudes of the sum channel and
various difference channels for example, it is thus possible to
locate the reflecting object within the radar beam. It is also
possible to form a difference channel by an antiphase coupling of
the left to the right antenna groups.
[0005] An example antenna array according to the present invention
for a radar transceiver and the circuit configuration for supplying
the primary exciter patches of such an antenna array may
advantageously allow for the antenna to be operated according to
the so-called monopulse method. In particular, it becomes possible
to switch between two antenna characteristics. This makes it
possible to achieve an angular measurement that is extraordinarily
advantageous in a radar sensor. It is particularly advantageous
that the antenna array according to the present invention allows
for the monopulse principle to be used for an antenna design that
has primary exciters situated on a carrier, in particular a chip.
This allows for a simple manufacture and a simple operation.
[0006] Thus, an advantageous specific embodiment provides for the
one carrier to be a chip. The example embodiment of the carrier as
a chip has the great advantage of allowing the antenna array to be
implemented on a semiconductor circuit having an integrated primary
exciter. In this regard, it is particularly advantageous if no
additional external components are required for operating such an
antenna array. In particular, the chip may also contain the circuit
device for controlling the primary exciter patches. It is also
possible, however, to develop this carrier as a circuit board, as a
soft board substrate or a circuit film.
[0007] The other, additional carrier may be a circuit board and/or
a soft board substrate or a circuit film.
[0008] A particularly preferred specific embodiment provides for
the two carriers to be fastened to each other and contacted using
flip chip connections. Advantageously, these flip-chip connections
are generally implemented by generally spherical soldering
connections. In this manner, it is possible to achieve a very
simple manufacture and at the same time good contacts.
[0009] With respect to the position of the secondary exciter
patches, various specific embodiments are possible.
[0010] A first advantageous specific embodiment provides for both
secondary exciter patches to be situated either on the top side or
on the bottom side of the additional carrier or one on the top side
and the other on the bottom side of the additional carrier.
[0011] The position is generally a function of the frequency at
which the antenna array is operated and depends on the field of
application. In addition to this position of the secondary exciter
patches above the primary exciter patches, the height of the
contact elements, which amounts, e.g., to 70 .mu.m, and the
thickness of the circuit film, which may vary, e.g., between 50 and
300 .mu.m, are, aside from the material properties, the determining
main parameters for optimizing the dimensions of the primary
exciter patches and the secondary exciter patches.
[0012] The supply terminals of the primary exciter patches are
connected on the longitudinal edges of the primary exciter patches.
The terminal positions of the supply lines may basically be chosen
at will and are merely determined by a specifiable desired
impedance. The (end) positions of the supply terminals on the
primary patches are selected as a function of a desired input
impedance of the antenna.
[0013] Not only to protect the antenna array against environmental
effects, but also with a view to achieving optimal electrical
properties of the antenna, there may be a further provision of
introducing an encapsulating material embedding the primary exciter
patches and the secondary exciter patches into the space between
the two carriers or to introduce a so-called underfiller on an
epoxide resin basis and to use it to fill this space.
[0014] Such an antenna is operated using a circuit configuration
for supplying the primary exciter patch, which has a switching
device, in the first switch position of which a high-frequency
signal may be applied on the supply terminal of the first primary
exciter patch and a high-frequency signal having a phase shift
around 180.degree. may be applied on the supply terminal of the
second primary exciter patch, and in the second switch position of
which respectively an in-phase high-frequency signal may be applied
on the supply line of the first primary exciter patch and on the
supply line of the second primary exciter patch.
[0015] These two switch positions allow for two different antenna
characteristics, namely, a sum antenna characteristic having only
one beam cone and a difference antenna characteristic having two
beam cones. Another advantageous specific embodiment additionally
provides for controlling the amplitude of the high-frequency signal
that is applied on one of the two supply terminals. This makes it
possible to achieve a swiveling of the antenna characteristic.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Exemplary embodiments of the present invention are shown in
the figures and explained in greater detail below.
[0017] FIG. 1 shows a schematic top view of the structure of an
example antenna array according to the present invention together
with an example circuit device according to the present
invention.
[0018] FIG. 2 shows an isometric view of the structure of an
example antenna array on a semiconductor chip.
[0019] FIG. 3 shows the antenna characteristic according to a first
switch position of the switching device.
[0020] FIG. 4 shows the antenna characteristic according to a
second switch position of the switching device.
[0021] FIG. 5 shows the antenna diagram of a straight beam and of a
beam swiveled by 10.degree..
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
[0022] FIG. 1 and FIG. 2 schematically show an antenna array for a
radar transceiver, in particular for ascertaining distance and/or
speed in the surroundings of vehicles.
[0023] A first antenna part is situated on a carrier, for example
on a chip 5. The first antenna part has two generally rectangular
primary exciter patches, a first primary exciter patch 10 and a
second primary exciter patch 20, which adjoin each other on a
narrow edge, where they are jointly short-circuited toward ground
via a ground connection 40. The two primary exciter patches 10, 20
each have a length l, which corresponds approximately to a fourth
of the wavelength of the mm or .mu.m wave to be emitted.
[0024] On the end of primary exciter patches 10, 20 facing away
from ground connection 40, the electromagnetic wave takes off and
excites the secondary exciter patches 51, 52 situated above primary
exciter patches 10, 20. Secondary exciter patches 51, 52 are
situated at a specifiable distance above primary exciter patches
10, 20--as shown schematically in FIG. 2. The selection of the
distance depends on the wavelength of the emitted radar beam and is
approximately between 100 and 150 .mu.m.
[0025] Secondary exciter patches 51, 52 are situated for example on
another carrier 59, which is represented in FIG. 2 as transparent
for a better overview. This carrier 59 may be a film, a circuit
board, a soft board substrate or a circuit film.
[0026] Carrier 5 is preferably connected and contacted with carrier
59 via flip-chip connections 80.
[0027] The first primary exciter patch 10 is connected to a supply
line 11. Second primary exciter patch 20 has a separate supply line
12. Supply lines 11, 12 contact an edge of first and second primary
exciter patch 10, 20 and lead into first and second primary exciter
patches 10, 20. The choice of the position, at which supply lines
11, 12 respectively lead into first and second primary exciter
patch 10, 20, may be made at will, it being generally determined by
a specifiable input impedance. This means that the position is
chosen in such a way that a desired input impedance is
achieved.
[0028] The space between carrier 5 and the additional carrier 59
may be filled by an encapsulating material 90, in particular a
silicone gel or a so-called underfiller on epoxide resin basis,
which embeds primary exciter patches 10, 20 and secondary exciter
patches 51, 52. Not only is the antenna array thereby protected,
but this measure in particular also allows for the radar antenna
array to be optimized--in addition to the choice of the height of
the contact elements, which is preferably, e.g., 70 .mu.m, and the
choice of the thickness of the circuit film, which is preferably
between 50 and 300 .mu.m.
[0029] For supplying the two primary exciter patches 10, 20, a
circuit configuration 100, shown schematically in FIG. 1, is
provided, which has a switching device 110 for switching between
two switch positions 1, 2. In a first switch position 1, the two
supply lines 11, 12 are each supplied with high-frequency signals,
which have a phase shift of 180.degree. (switch position
.SIGMA.--sum). This means, for example, that a high-frequency
signal having a phase P is supplied to supply line 11 and a
high-frequency signal having a phase P+180.degree. is supplied to
supply line 12. This results in the "sum" antenna characteristic
shown in FIG. 3 having a single beam cone.
[0030] On the other hand, if in switch position 2 an in-phase
high-frequency signal is supplied to first supply line 11 and to
second supply line 12 (switch position .DELTA.--difference), then
the "difference" antenna characteristic having two beam cones is
produced as shown in FIG. 4.
[0031] A beam swivel by up to +10.degree. may be achieved by
controlling the amplitude of the high-frequency signal applied on
supply terminal 12. In FIG. 5, a dot-dash line 501 shows a
non-swiveled antenna characteristic having a high-frequency signal
on supply line 11 and having a high-frequency signal of the same
amplitude and a phase shift of 180.degree. on supply line 12. Line
502 represents an antenna characteristic swiveled by 10.degree., in
which second supply line 12 has a high-frequency signal applied to
it, having an amplitude corresponding to half the amplitude of the
signal supplied to first supply line 11, and again having a
180.degree. phase shift between the two supply lines 11, 12.
Depending on the choice of amplitude, a rotation of the antenna
characteristic may be achieved.
[0032] In addition to primary exciter patches 11, 12, parts of an
integrated circuit are positioned on carrier 5, for example circuit
configuration 100 or other or additional circuit devices.
[0033] The antenna array is operated for example at a working
frequency of 122 GHz. Typical dimensions at this working frequency
are for example the following length and width ratios of primary
exciter patches 10, 20: 295 .mu.m.times.160 .mu.m, secondary
exciter patches 51, 52 in this case having length and width ratios
of 1050 .mu.m.times.400 .mu.m for example. The distance between the
primary and secondary exciter patches is approximately 100 .mu.m.
As may be gathered in particular from FIG. 1 and FIG. 2, secondary
exciter patches 51, 52 are situated at a distance A in such a way
that a space or a gap remains free between them, which exposes the
joint ground contact 40 of the adjoining primary exciter patches
10, 20 in the beam direction.
[0034] It should be pointed out as well that secondary exciter
patches 51, 52 may be situated on both sides of carrier 59. The
arrangement is a function of the frequency and the application.
[0035] In summary it may be said that the above-described design of
the antenna array according to the present invention and the
circuit configuration for operating such an antenna array make it
possible to implement a monopulse operation for producing different
antenna characteristics in an antenna that is very advantageously
able to be developed or situated on a chip.
* * * * *